Metal clad switch



Oct. 28, 1941. R. P. MATTERN 2,260,754

METAL CLAD SWITCH Filed May 31,/ 1940 Patented Oct. 28, 1941 l 2,260,754` A METAL CLAD' SWITCH Raymond P.

Mattern, Minneapolis, Minn., as-

signor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn.,

Delaware a corporation of Application May 31, 1940, Serial No. 337,962

11 Claims.

This invention relates to improvements `in the field of duid filled switchesfparticularly of the metal clad type. v

One of the main objects of the present invention is to provide a metal clad switch which has a minimum munber of parts, is simple and inexpensive to manufacture, and which is small. compact, and yet durable under reasonably heavy loads.

Another object is to provide a metal clad switch having a pair of opposed metal cups, a partition of insulatingV material to separate them, and an insulating cover to hold them in assembled relation.

A further object of the invention is to leave a portion of the ends of the metal cups exposed to cooperate with resilient mounting members which rotatably support said switch and form the electrical connections4 thereto.- c

A still further object is to provide thecups with outwardly extending flanges which may act to compress a rubber gasket to aid in sealing the switch when the insulating cover holds the cups in place.

Still anotherobject is to vulcanize the rubber gasketgdirectly to the cups in order to more positively seal the switch.

These and other objects will readily become apparent asthe followingspecification is read in the light of the accompanying drawing, in which:

Figure 1 is a general view ofthe button or rotary type switch and the mounting means therefor, the switch itself being shown in section;

Figure 2 is an end in Figure 1;

Figure 3 is a section/ of the switch shown in Figure 1 taken along the line 33;

Figure 4 is a detail view of a modied form f insulating partition which may be sistituted in the switch of Figure l'if desired;.

Figure 5 is a section taken along the'line 5--5 of Figure 4, 'and Figure 6 is a sectional view of the 'elongated or elevation of the device shown tubular switch.

A ny electrically conductive uid may be used in this switch but for the purpose of this descrip-J which is the most commonly used for this purposel The button Figure 1 isconip'osed of a pair of opposed metal cups I0 and II which are adapted to seat on the annular shoulders I2 and I3 in the partition Il.

This partition is composed of material which is electrically insulating and also arc resistant. In this particular case, the material lchosen isa high strength moulded ceramic. The metal cups I0 and II are provided with outwardly extending annular flanges I5 and I6, which with the periphery I1 of the partition yI4 form an annular channel. A synthetic rubber gasket I8 is located in this channel and is normally slightly wider than the channel so that as the cups I0 and Il are forced into engagement with the shoulders I2 and I3, the gasket I8 is compressed, thus sealing the enclosure formed by the metal cups from the external air. ,In order to improve this seal, the gasket I8 may if :desired be vulcanized to the cups.

The [cups I0 and II are provided with shoulders 20 and ZI and insulating cover 22 made up of a thermo-setting material such as Bakelite, is formed under pressure around the circumference of the switch and in engagement with the shoulders 20 and 2i on the metal cups I0 and II.

. As the cover 22 is moulded around the switch,

considerable pressure is applied and the-two cups I0.and II are forced against the shoulders i2 and I3 in the partition I4, thereby compressing the gasket I8 and forming -a good seal for the switch. When the Bakelite cover hardens, it holdsthe parts iirmly in their assembled position.

When the switch is being made, a'small opening is left in one of the metal cups so that the'air l'may be evacuated from the enclosure and the switch filled with the proper amount of mercury and hydrogen gas. It will be seen that the partition I4 divides the enclosure into two chambersv and separates the mercury into two separate pools 24 and 25. An opening 26 is placed near the periphery of the partition I4 and with the switch in Nthe position shown in Figure 1, this opening is above the level of the mercury and -therefore the two metal cups I0 and I I are electrically separated. When the switch is rotatgdQ however, the hole 26 will move below the surface of the mercury and the two pools 24 and 25 will trically connect the two cupsl and I'I.

tion this duid will be referred to as mercury,

or rotary type switch disclosed in elec- One form which this opening can take is shown at 26 in Figure 3, the level of the mercury being shown by the dotted line 21.

. As-shown in Figure 3, the lower edge 28 of the ilow together through the opening 26 'and opening 26 is'the edge which finally separates the Atwo pools of mercury 24 and 25 as the switch is rotated' in a clockwise direction. As shown in Figure 1, this edge extends straight through the partition and as a result the mercury break may occur at either one or the other ends of the hole. As a result, under heavy lelectrical loads the arc may sometimes strike one'or the other of the metal cups directly thereby erroding the cups and contaminating the mercury. Therefore it is desirable, particularly under heavy loads, to design a partition in which the break between the two pools of mercury will always occur midway of the partition. The partition 45 disclosed in Figures 4 and 5 was designed with this object in view. In this form of partition, the breaking edge of the opening 46 isin the form of a V with the point 41 of the V midway of the partition. In this case the break will always occur. at the point of the V which is at a maximum distance from the two cups and therefore the probability of the arc impinging directly onto one of the metal cups is lessened. As shown in Figure 4, the gradual sloping sides 48 oi the V extend in an'arc around the partition, which arc lies on a circle concentric with respect to the axis of rotation of the switch.

The switch is supported by means of a pair of brackets 30 and 3| which are suitably connected to a supporting member 32. The bracket 30 is provided with`a washer shaped end 33 which fits over a projection 34 onv the .exposed end of the cup l0. The member 30 is also provided with a pair of resilient lingers 35 and 36 which are biased into engagement with the face 31 of Vthe cup I 0. The bracket 3l is provided with duplicate parts 33, 35, and 36 which cooperate with the cup Il in exactly the same manner. 'I'hese two brackets act to rotatably support the switch, and the three members 33, 35, and 36 which frictionally engage the faces of the metal cups act to electrically connect them in a circuit which may in turn be connected to' the brackets 30 and 3| through the binding posts 38 and 39.

In order to rotate this switch, an insulating arm 40 may be suitablyv cemented or otherwise attached to the periphery of the switch, as shown in Figures 2 and 3. This handle may also be molded on the cover and form an integral partof it if desired. This arm 4|).may extend through an opening 4l in a wall plate 42 where the switch is used for operating a house lighting circuit. It will be seen in connectionA with Figure 3 that if the arm 40 is in its raised position, the opening 26 will be above the level of the mercury and thereforethe circuit through the switch will be broken. When the arm 40 is moved downwardly as indicated in dotted lines in Figure 3, the opening 26 will be below 'thelevel of the mercury and the circuit through this switch will be closed.

Figure 6 discloses an elongated or tubular type metal mercury switch. As in the case of Figure l, two metal cups 5l and 52 are seated on opposite annular shoulders 53 in the partition 54.-

Thepartition 54 mmay be made of the same material as the partition in Figure l. These cups are also provided with outwardly extending flanges 55 which compress a rubber gasket 56 as the cups are forced against the shoulder 53. If desired, the gasket 56-may be vulcanized to the metal cups in order to improve the seal between the enclosure and theoutside air. A 52 is providedwith an outwardly extending stem 58 which acts as oneelectrode terminal for the switch. The cup 5l is provided with an outwardly extending hollow stem 5,9. ABakelite cover 60 is moulded about the switch lunder pressure so as to hold the cups 5V! and 52 firmly in engagement with the shoulder 53.. After these parts have been assembled `.the switch may be The metal cup' evacuated and lled-with mercury and hydrogen gas through the hollow stem 59 which may then be sealed ofi. This stem acts as the-other elec-y trode terminal for the switch.

The partition 54 is provided with a tapered hole 62 which extends through the center to provide a path through which the mercury within the switch vmay extend to electrically connect the two metal cups 5l and 52. Inasmuch as this hole 62 is concentric with respect to the axis of the switch, the Arotative position of the switch is immaterial, The circuit is controlled entirely by tipping the switch one way or another. As the switch is tipped to al position where the stem 58 is higher than the stem 59, the mercury will 'ow` illustrative purposes only and therefore I wish to be understood that I am to be limited only by the scope of the appended claims and not'by the specific forms.

I claim as my invention: n

l. A switch comprising in combination, a pair, of oppositely positioned dished metal cups, a partition of insulating material interposed between said cups separating them electrically, said cups seating on said partition, a vquantity of electrically conductive fluid partially iilling said cups, said fluid beingv separated into two pools by said partition, an opening in said partition whereby said two pools of fluid are connected through said opening for certain positions of said switch, la resilient gasket between said cups, and an insulating cover for said switch, said coveracting to holdsaid cups in a position to compress said gasket therebyaiding in sealing said switch.

2. A switch comprising in combination, a pair ofy oppositely positioned .dished metal cups, a partition of insulating material interposed between said cups separating them electrically, said cups seating on said partition, a quantity of electrically conductive uid partially lling said cups,

[said yiluid being separated into` two pools by said partition, an opening in said partition whereby said two pools of uid are connected through said opening for certain positions of said switch,

flanges on .said cps extending outwardly'beyond v the ,periphery of saidpartition, a resilient gas- .n ket around said partition between said flanges, a

quantity of electrically conductive uid partially iilling saidcups and separated into two pools by said partition, an opening in said partition whereby saidtwo pools 'are connected through said opening for certainpositions of said. switch, and an ,insulating cover for saidswitch, said .cover acting to hold said cupsagainst said shoulders to compress said gasket and seal said switch.

4. A switch comprising in combination, a partition of insulating material, said partition having oppositely. disposed'shoulde'rs, a pair of dished metal cups adapted to seat .en A said shoulders,

flanges on said cups extending outwardly beyond the periphery of said partition. Va resilient iras,

ket around said partition between said anges, a quantity of electrically conductive iiuid partially lling said cups and separated into two pools by said partition, an opening in said partition whereby said two pools are' connected through said opening for certain positions of said switch, and a cover of thermosetting material moulded about said switch, said cover holding said cups against said shoulders and compressing said gas-- ket to seal said switch. e

5. A switch comprising in combination, a pair of oppositely positioned dished metal cups. a partition of insulating material interposed between said cups separating them electrically, said cups seating on said partition, a quantity of electrically conductive uid partially liing said cups, said fluid being separated into to pools by said partition, an opening in said partition whereby said two pools of uid are connected through said opening for certain positions of said switch, a rubber gasket located between and vulcanized to `said cups, and an insulating cover for said tions oi' said switch, an annular shoulder in the end of each of said cups, an insulating cover ex- 'tending circumferentially around said switch.

and tting into said shoulders to hold said cups and partition in assembled relation, said cover leaving a substantial part of the ends ofsaid cups exposed, and a` pair of resilient supporting members, the exposed ends of said cups includswitch, said cover acting to vhold said cups in a position to compress said gasket.

6. A rotary type switch comprising in combination, a switch enclosure, a partition of electrically insulating material dividing said enclosure into twok parts, a quantity of electrically conductive uid in each part, and a relatively small opening near the periphery of said partition whereby connection between the two parts of said fluid will be alternately made and broken through said opening as said switch is rotated back and forth, that part of said partition which forms the breaking edge of said opening being in the form 'of a V with the point of the V 'substantially midway of the partition whereby the pools by said partition, an opening in said parti- -tion whereby said two pools of uid are con-v nected through said opening for certain positions of said switch, and an insulating cover circumferentially around said switch and extending partially over the ends to hold said cups and partition in assembled relation and at the same Itime leave a substantial portion of the ends of said cups exposed.

8. A switch comprising in, combination, a pair of oppositely potioned dished metal cups, a partition of insulating material interposed between said cups separating them electrically, a quantity of electrically conductive iluid ypartially illling said cups. said Huid being separated into two pools by said partition, an opening in said partition whereby said tworpools of huid are connected through said opening for certain posiing means for frictional cooperation with said supporting members for rotatably supporting said switch.

9; A switch comprising in combination, a pair of oppositely positioned dished metal cups, a partition ofF insulating material interposed between said cups separating them electrically, a quantity of electrically conductive fluid partially filling said cups, said-huid being separated in to two pools by said partition, an opening in said partition whereby said two pools of uid are connected through said opening for certain positions of said switch, an outwardly extending stem integrally connected to each cup, and an insulating cover moulded to said switch and stems and holding said cups and partition in assembied'relation, said stems extending through said cover and constituting electrode terminals for said switch.l y

10. A switch comprising in combination, a pair of oppositely positioned dished metal cups, a partition of insulating material interposed between said cups separating them electrically, a quantity of electrically conductive' uid partially lling said cups, said fluid being separated into two pools by said partition, an opening in said partition whereby said two pools of iiuid are con-k nected through said opening for certain positions of said switch, an outwardly extending stem integrally connected Vto each cup, and an insulat; ingcover, moulded to said switch and stems and holding said cups and partition in assembled relation, said stems extending through said cover and constitutingelectrode terminals for said switch, one of said stems being hollow so that said switch may be evacuated and filled through said stem.. Y 11.A switch comprising in combination, a disc shaped partitionof insulating material having oppositely disposed circumferential shoulders, a

pair of oppositely disposed cup shapedterminals havin'g portions seating in said shoulders and circumferential flanges extending outwardly in substantially parallel planes, a quantity of elec- "trically conductive fluid partially lling said cup 

